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Ajamaluddin Malik

Associate Professor

Associate Professor

كلية العلوم
Building no 5, room no 2A56
المنشورات
مقال فى مجلة
2005

Use of enhanced green fluorescent protein to determine pepsin at high sensitivity

, Ajamaluddin Malik, Rainer Rudolph & Brigitte Söhling . 2005

A fluorometric assay for pepsin and pepsinogen was developed using enhanced green fluorescent protein (EGFP) as a substrate. Acid denaturation of EGFP resulted in a complete loss of fluorescence that was completely reversible on neutralization. In the proteolytic assay procedure, acid-denatured EGFP was digested by pepsin or activated pepsinogen. After neutralization, the remaining amount of undigested EGFP refolded and was determined by fluorescence. Under standard digestion conditions, 4.8-24.0 ng pepsin or pepsinogen was used. Using porcine pepsin as a standard, 38+/-6.7 ng EGFP was digested per min-1 ng pepsin-1. Activated porcine pepsinogen revealed a similar digestion rate (37.2+/-5.2 ng EGFP min-1 ng activated pepsinogen-1). The sensitivity of the proteolysis assay depended on the time of digestion and the temperature. Increasing temperature and incubation time allowed quantification of pepsin or pepsinogen in a sample even in the picogram range. The pepsin-catalyzed EGFP digestion showed typical Michaelis-Menten kinetics. Km and Vmax values were determined for the pepsin and activated pepsinogen. Digestion of EGFP by pepsin revealed distinct cleavage sites, as analyzed by SDS-PAGE.

رقم المجلد
340
مجلة/صحيفة
Analytical Biochemistry
الصفحات
252-258
مزيد من المنشورات
publications

Polyphosphate polymers are chains of phosphate monomers chemically
bonded together via phosphoanhydride bonds. They are found in all prokaryotic and
eukaryotic organisms and are among…

بواسطة Ajamaluddin Malik, Javed Masood Khan, Abdulaziz M. Al-Amri, Nojood Altwaijry, Prerna Sharma, Abdullah Alhomida, Priyankar Sen
publications

Phosphate additions in processed foods are a health risk that has been overlooked. This study examined the
effects of a permitted food additive (E452; Sodium Hexametaphosphate (SHMP)) on…

بواسطة Ajamaluddin Malik, Javed Masood Khan, Abdulaziz M. Al-Amri, Nojood Altwaijry, Abdullah S Alhomida, Mohammad Shamsul Ola
2023
publications

Protein aggregation is implicated in different human diseases. It also makes the protein less desirable candidate for industry as they exhibit reduced biological activity. Proteins tend to…

بواسطة Javed Masood Khan, Ajamaluddin Malik, Abdulaziz M. Al-Amri.
2023
تم النشر فى:
Journal of Molecular Liquids